The present invention relates generally to optical scanners which are used to scan a closely adjacently positioned object such as a document and, more particularly, to a converter for an optical scanner which enables the scanner to scan a scene remote from the scanner.
Optical scanners which create electronic data representative of an image of a scanned object are known in the art. Flat bed scanners are stationary devices which have a transparent plate or platen upon which an object to be scanned, such as a paper document, is placed. The document is scanned by sequentially imaging narrow strip or scan line portions of the document on a linear optical sensor array such as a charge coupled device (CCD). The optical sensor array produces electronic data which is representative of each scan line portion of the document which is imaged thereon. In one type of flat bed scanner the current scan line portion of the document which is imaged on the sensor array is changed or "swept" by moving the platen supporting the document relative to the scanner imaging assembly. In another type of flat bed scanner the platen and document remain stationary and at least a portion of a imaging assembly is moved to change the scan line portion which is currently imaged. Flat bed scanners of the second type are sometimes provided with automatic document feeders (ADFs) which sequentially move sheet documents across a portion of the scanner platen. When an ADF is used, the portion of the imaging assembly which ordinarily moves during scanning remains stationary and relative movement between the document and imaging assembly is provided by the ADF. Flat bed scanners and ADF's are disclosed in the following patents, each of which is hereby incorporated by reference for all that is disclosed therein: Boyd et al., U.S. Pat. No. 4,926,041; Boyd et al., U.S. Pat. No. 5,336,878; Henry et al., U.S. Pat. No. 5,339,107, Steinle et al., U.S. Pat. No. 5,410,347; and Steinle et al., U.S. Pat. No. 5,646,394.
Portable or hand scanners, like flat bed scanners, generate electronic data representative of an image of an object by sequentially imaging scan line portions of the object. However hand scanners differ from flat bed scanners in that hand scanners produce relative movement between the scanned object and the scanner imaging assembly by displacing the entire scanner relative to the document. Hand scanners generally have an end portion which is adapted to be positioned in contact with the object which is to be scanned. An operator moves the scanner over the object keeping this end portion in contact with the object. Since the displacement between the scanner and the object is provided by the user rather than a fixed speed drive assembly such as contained on a flat bed scanner, a displacement sensing assembly is usually provided on a hand scanner in order to properly correlate and arrange the sequential scan line image data generated by the optical sensor array to enable reproduction of an accurate composite image of the object. Hand scanners and displacement sensing systems or navigation systems therefore are disclosed in the following patents, each of which is hereby specifically incorporated by reference for all that is disclosed therein: Allen et al., U.S. Pat. No. 5,644,139; McConica et al., U.S. Pat. No. 5,586,212 Allen et al., U.S. Pat. No. 5,578,813; Kochis et al., U.S. Pat. No. 5,381,020; McConica et al., U.S. Pat. No. 5,306,908; Reymond et al., U.S. Pat. No. 4,494,201; Postl, U.S. Pat. No. 4,723,297; Mongomery et al., U.S. Pat. No. 4,797,544; Hollister, U.S. Pat. No. 4,951,214; Abramovitz et al., U.S. Pat. No. 5,023,922; Holland, U.S. Pat. No. 5,089,712; Sobol, U.S. Pat. No. 5,185,673; Chiu et al., U.S. Pat. No. 5,355,146; and Kimura et al., U.S. Pat. No. 5,497,150.
Both flat bed scanners and hand scanners used to date require that an object which is to be imaged be positioned in touching contact with or in very close proximity with the object which is scanned. It would be generally desirable to provide a converter which would enable a flat bed scanner or a portable scanner to be used to scan objects positioned remotely from the scanner. It would be particularly desirable to provide such a converter for a portable scanner to enable the scanner to be used, in effect, as a portable digital camera as well as a portable optical scanner.